Abstract
Earthworm basics Earthworm species play a significant role not only in soil formation and aeration, but also in nutrient cycling, climate regulation, pollution remediation, and primary production (Blouin et al. 2013). Forests once had a thick coating of "duff," a layer of decomposing plant and animal materials above the soil's A-horizon, but earthworms have accelerated the rate of duff decomposition through consumption and mixing of soil layers. The once thick duff layer supported germination of a number of native plant species, but with its loss, ground-dwelling organisms such as the blue-spotted salamander and the ovenbird have lost valuable habitat (Hale 2013). To ensure a safe learning environment, as students weigh and mix the mustard with the water, they should wear eye protection.